/Engine/Source/Runtime/Slate/Public/Framework/Application/SlateApplication.h
Finds the window that the provided widget resides in
The window where the widget resides, or null if the widget wasn't found. Remember, a widget might not be found simply because its parent decided not to report the widget in ArrangeChildren.
virtual [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [SWindow](API\Runtime\SlateCore\Widgets\SWindow) > FindWidgetWindow ( [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< const [SWidget](API\Runtime\SlateCore\Widgets\SWidget) > InWidget ) const